Try spinning the throw out bearing by hand. It should be smooth with little to no resistance.
For the tip of the shaft, clean it up with emory cloth.
Did you inspect every spline on the input shaft for a dimple or burr? It doesn’t take much to give the clutch plate something to hang up on.
While you have the slave cylinder out, try gravity bleeding it again, this time angle it so the bleeder valve is the highest point. That way any trapped air will be forced out.